I was thinking about this, but I think the Cubs are done with their bullpen, especially after signing Duensing. I know guys want a typical closer and if you can find a guy like that who is super valuable (i.e Chapman in 2016, Jansen, etc) then go for it but otherwise, I don't think you really want a closer as much as you want two or three guys who can get outs late in game. My assumption is that Morrow will lead the team in saves but I wouldn't be shocked if three or four guys didn't get multiple opportunities to get outs game to game. Then, in the playoffs, you potentially add Chatwood to the bullpen and his stuff might be electric in that type of role in the playoffs, I think they'll be fine.
Basically the hope for the bullpen is you lost Davis but you're hoping to basically add three high leverage arms back (Wilson, Morrow, Cishek) that cost literally the same dollars as Wade and gave you zero valuable innings in the playoffs where as those guys could give you 2-3 times what Wade gave you.
If everyone is completely healthy, I think the first crack bullpen is
8th/9th - Morrow, Cishek
7th/8th - Edwards, Wilson, Strop
6th/7th/Mop Up - Last guy in the pen, Montgomery, Duensing